A thermally transferred image-receptive sheet used for thermal transfer printing utilizing thermal transfer imaging or sublimation transfer imaging requires clarity of the image. Important factors in the clarity are smoothness and cushioning properties of the surface of the image-receptive sheet.
On the other hand, from a viewpoint of handling, such as outdoor use and the like, the image-receptive sheet requires strength, resistance to folding, permanence properties and resistance to water in some cases.
As a thermally transferred image-receptive sheet possessing simultaneously smoothness, cushioning properties and strength, there have been thermally transferred image-receptive sheets wherein a polyamide or polyurethane microporous layer is provided on a substrate, such as woven fabric and nonwoven fabric. These types of thermally transferred image-receptive sheets have been generally produced by coating a nylon coating composition containing calcium chloride, methanol and nylon as a main component or a polyurethane coating composition containing dimethylformamide and polyurethane as a main component on a substrate, dipping the coated substrate to form a nylon or polyurethane microporous layer while leaching out the solvent and the like (for example, see JP-A 03-021487).
In such prior art, the coated substrate was dipped into water, dried and furnished. In the furnishing step, regarding a cover factor of woven fabric, a ratio of a cover factor thereof immediately after coating relative to that of a final product (referred to as "a cover factor ratio" hereinafter) was relatively large (a cover factor ratio was above 1.03). Alternatively, another attempt was tried by carrying out such furnishing step, followed by a calendering step.
On the other hand, there has been a demand for high clarity of the image. In order to respond to this demand, smoothness of a thermally transferred image-receptive sheet obtained by a process wherein a relatively large cover factor or a roll method (calendering method) is used is required to be further improved.